After 100 years: a detailed view of an eumalacostracan from the Upper Jurassic Solnhofen Lagerstätte with raptorial appendages unique to Euarthropoda

PAULA G. PAZINATO , CLÉMENT JAUVION , GÜNTER SCHWEIGERT, JOACHIM T. HAUG AND CAROLIN HAUG

Pazinato, P. G., Jauvion, C., Schweigert, G., Haug, J. T., & Haug, C. 2020: After 100 years: a detailed view of an eumalacostracan crustacean from the Upper Jurassic Solnhofen Lagerstätte with raptorial appendages unique to Euarthropoda. Lethaia, https://doi.org/10.1111/let.12382.

The Solnhofen Konservat‐Lagerstätte yields a great number of remarkably preserved fossils of eumalacostracan that help us understand the early radiation of several groups with modern representatives. One fossil from there, Francocaris grimmi Broili, 1917 is a small ‐like crustacean originally described about 100 years ago as a mysidacean crustacean (opossum and relatives) from latest Kimmeridgian – early Tithonian (Upper Jurassic) of the Solnhofen Lithographic Limestones of South- ern Germany. New material with exceptionally preserved specimens, allied with mod- ern imaging techniques (mostly composite fluorescence microscopy), allows us to provide a detailed re‐description of this species. The most striking feature of Franco- caris grimmi is an extremely elongated thoracopod 7 with its distal elements forming a spiny sub‐chela. This character supports a sister group relationship of Francocaris grimmi with , an ingroup of , pelagic peracaridans common in marine environments throughout the world. We also discuss other supposed fossil representatives of Lophogastrida, identifying all of them as problematic at best. The structure of the sub‐chela in F. grimmi indicates an original use in raptorial behaviour. Francocaris grimmi appears to be unique in possessing such a far posterior sub‐chelate appendage as a major raptorial structure. In most representatives of Euarthropoda in which sub‐chelate appendages occur and are used for food intake, they are usually clo- ser to the mouth. □ Euarthropoda, eumalacostracan crustacean, Lophogastrida, rapto- rial, Solnhofen Lagerstätte, Upper Jurassic.

Paula G. Pazinato ✉ [[email protected]], Joachim T. Haug [[email protected]], Carolin Haug [carolin.haug@palaeo-evo- devo.info], Department of Biology II, LMU Munich, Großhaderner Straße 282152, Pla- negg‐Martinsried, Germany; Clément Jauvion [[email protected]], Muséum national d'Histoire naturelle, CNRS UMR 7207, CR2P, Centre de Recherche en Paléon- tologie ‐ Paris, Sorbonne Université, 8 rue Buffon, 75005, Paris, France; Clément Jauvion [[email protected]], Muséum national d'Histoire naturelle, CNRS UMR 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Sorbonne Université, 61 rue Buffon, 75005, Paris, France; Günter Schweigert [guen- [email protected]], Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1 70191, Stuttgart, Germany; Joachim T. Haug [[email protected]], Carolin Haug [[email protected]], GeoBio‐Center, LMU Munich, Richard‐Wagner‐Straße 1080333, München, Germany; manuscript received on 5/09/ 2019; manuscript accepted on 7/02/2020.

Today, malacostracan crustaceans are among the sense (Barthel 1978; Barthel et al. 1990; Arratia most prominent non‐vertebrate components of fau- et al. 2015). nas, especially of the marine environments. A The lithographic limestones of Southern Germany major diversification of the group occurred in the have yielded especially numerous representatives of late Palaeozoic and many of the modern lineages (Oppel 1862; Schweigert & Garassino have fossil representatives in the Mesozoic (Klomp- 2004; Garassino & Schweigert 2006; Schweigert 2011, maker et al. 2013). Our knowledge of the history of 2015; Schweigert et al. 2016), but also several repre- malacostracan crustaceans is, in many aspects, very sentatives of Stomatopoda (Haug et al. 2009a, 2010). detailed due to the presence of Konservat‐Lagerstät- This also includes spectacularly well‐preserved larval ten containing fossils with exceptional preservation. forms of both groups, only known from very few Among these are the Upper Jurassic lithographic other localities. Among them are modern‐looking limestones of Southern Germany, also referred to larvae of spiny lobster‐like crustaceans (Polz 1972, as Solnhofen Lithographic Limestones in a wide 1973; Haug et al. 2011a, 2014a), now extinct larval

DOI 10.1111/let.12382 © 2020 The Authors. Lethaia Published by John Wiley & Sons Ltd on behalf of Lethaia Foundation This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. 2 Pazinato et al. LETHAIA 10.1111/let.12382 types of spiny lobster‐like crustaceans (Polz 1996; older deposit than the overlying Zandt Member, Haug et al. 2009b, 2013; Haug & Haug 2013, 2015, according to high‐resolution biostratigraphical data 2016; 2014a), remains of larval clawed lobsters (Haug based on ammonite assemblages (Schweigert 2007). & Haug 2017), modern‐looking types of mantis The most recent discoveries of Francocaris grimmi shrimp larvae (Haug et al. 2008, 2015) and now are specimens from the Lower Tithonian Mörnsheim extinct larval forms of mantis shrimps (Haug et al. Formation of Daiting. Francocaris grimmi has not 2009a, 2015). Likewise, representatives of yet been detected outside the Franconian Jurassic. are well known from the lithographic limestones of Southern Germany (Polz 1998, 2003, 2004). Peracarida is mainly represented by fossils of the Material and methods group and their close relatives (). A peracaridan ingroup that is more challenging con- Material cerning the fossil record is , which includes Stygiomysida, (opossum shrimps) All available specimens considered to represent the and Lophogastrida. The last two groups have been species Francocaris grimmi Broili, 1917 were exam- suggested as being represented in the fossil record ined. The syntype series of Broili (1917) originally (Hessler 1969; Schram 1986; Feldmann et al. 2017), comprised five specimens, of which three are still yet most of the reported fossils remain problematic. available: SNSB – BSPG 2 I 17, 1917 I 2 and 1919 I 5 This also accounts for fossils from the lithographic (Fig. 2P, C, L, respectively). The other two specimens limestones of Southern Germany. Some fossils have are lost. Broili (1917) figured three specimens (his been interpreted as representatives of Mysidacea, but fig. A: SNSB – BSPG 2 I 17, fig. B: SNSB – BSPG all of them remain questionable (Röper 2005). 1919 I 5, fig. C: specimen lost). Since the original Mysidaceans are most likely less easily preserved description, better‐preserved material became avail- as fossils, as most of them lack the well‐calcified able and is presented here. The syntype series of shields and tergites that are present in representatives Broili (1917) and specimens SNSB – BSPG 1964 of Decapoda and Isopoda. However, as the litho- XXIII 592, 1982 I 78, 1983 I 153, 1983 I 154, 1984 I, graphic limestones of Southern Germany also pre- 1986 I, 1986 I 7, 1986 I 8, 1986 I 9 are deposited in served so many ‘soft’ larval forms, we should expect the Bayerische Staatssammlung für Paläontologie the preservation of the weakly calcified mysidaceans und Geologie in Munich. Specimens GSUB A241 as well. and GSUB A242 are deposited at the Geosciences We provide here a re‐description of the rather unusual‐looking shrimp‐like crustacean Francocaris grimmi Broili, 1917 from the lithographic limestones of Southern Germany. We discuss its possible iden- tity as a mysidacean, more precisely a lophogastri- dan, and its implications for lophogastridan evolution and diversification.

Geological setting

The records of Francocaris grimmi come from Soln- hofen‐type Konservat‐Lagerstätten (‘Solnhofener Plattenkalke’ in German) of Franconia, Bavaria, Southern Germany (Fig. 1), a series of laminated limestones that represent deposits of carbonate parti- cles in separated basins of low energy, confined waters at the northern margin of the Tethys Sea (Robin et al. 2013; Arratia et al. 2015). The fossils originally described by Broili (1917), and most of the new material available used for this study comes from the Konservat‐Lagerstätte Zandt, east of Eich- stätt in Bavaria. Some additional material is from the ‘ ’ Fig. 1. Map of Germany, illustrating the geographical sites of latest Kimmeridgian Öchselberg limestones, near Francocaris grimmi. Occurrences of the fossils are marked with the small village of Breitenhill, which is a slightly full dots. LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 3

Collection of the University of Bremen. Specimens Extant specimens of Eucopia grimaldii used for SMNS 70520/1, SMNS 70520/2 and SMNS 70520/3 comparison are from the Zoologische Staatssamm- are deposited at the Staatliches Museum für Natur- lung in Munich, and the specimen of Eucopia crassi- kunde in Stuttgart, all in Germany. From the 16 anal- cornis is from the Muséum national d'Histoire ysed specimens, two are preserved in ventral naturelle in Paris. orientation (SNSB – BSPG 1964 XXIII 592 and / SMNS 70520 1) and the remaining 14 are preserved Imaging methods in lateral orientation. Most of the samples are almost complete specimens; only pieces easily lost after the The specimens were documented either with micro‐ death of the are missing, such as appendages. or macro‐photography. The microscope used was an The impressions most likely represent actual corpses, inverse fluorescence microscope Keyence BZ‐9000, not exuviae, since the specimens are mostly articu- exploiting the auto‐fluorescence capacities of the lated and there is preservation of internal tissue. specimens (Haug et al. 2008, 2009a, 2011b). To

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Fig. 2. Composite auto‐fluorescence microscopy images of Francocaris grimmi specimens used for this study. All specimens to the same scale and with background removed. A, GSUB A242. B, SMNS 70520/1. C, SNSB – BSPG 1917 I 2. D, SNSB – BSPG 1986 I 7. E, SNSB – BSPG 1986 I 8. F, SNSB – BSPG 1983 I 154. G, SNSB – BSPG 1964 XXIII 592. H, GSUB A241. I, SMNS 70520/3. J, SNSB – BSPG 1986 I. K, SNSB – BSPG 1982 I 78. L, SNSB – BSPG 1919 I 5. M, SNSB – BSPG 1984 I. N, SMNS 70520/2. O, SNSB – BSPG 1986 I 9. P, SNSB – BSPG 2 I 17. Q, SNSB – BSPG 1983 I 153. Images C, G, H, I, O, P and Q were flipped horizontally. Original images can be found at: mor- phdbase.de. 4 Pazinato et al. LETHAIA 10.1111/let.12382 overcome the limited depth of field, stacks of images length of the shield/length of the prolongation of the were recorded with shifting focus. The specimens too shield. These two ratios were plotted against each large to fit into a single image were documented with other using LibreOffice (open source), and the plot several adjacent image details, each with a stack of was redesigned in Inkscape. images. The fossils showed good auto‐fluorescence under an excitation wavelength of 543 nm (TRITC, green light). For the extant specimens of Eucopia gri- Results maldii Nouvel, 1942, we used white light with phase contrast, the TRITC wavelengths and also an excita- General body organization tion wavelength of 360 nm (DAPI, UV light). For the extant specimens of Eucopia crassicornis Shrimp‐like body, slightly laterally compressed, Casanova, 1997 and the fossil specimen SMNS mostly preserved in lateral aspect; two specimens 70520/3, we used a Canon EOS Rebel T3i camera preserved in dorso‐ventral aspect, hence compression equipped with Canon MP‐E 65 mm macro lens. Illu- probably not strongly expressed (Fig. 2). Body orga- mination was either provided by a Canon MT24 EX nized presumably into 20 segments, ocular segment twin flash or two Yongnuo Digital Speedlite YN560 plus 19 post‐ocular segments, forming three major flashlights. Flashes were equipped with polarization functionally differentiated body regions: (1) func- filters. A perpendicular oriented filter was placed in tional head, including the ancestral eucrustacean front of the lens to achieve cross‐polarized light, head and some of the anterior thoracic segments enhancing contrast and avoiding reflections (Haug (cephalothorax) dorsally forming the shield; (2) a et al. 2011c). series of posterior thoracic segments (pereion) with To fuse the stack of images, we used Combine ZP separate tergites for each segment; and (3) six more (free software). Stitching of the fused images of the prominent segments forming the pleon (Fig. 3) and ® fossils was performed in Adobe Photoshop CS3. the telson articulated to it. For the images of the extant representatives, we used ® Adobe Photoshop Elements, using the Photomerge Functional head Panorama tool, either with the automatic algorithm or manual stitching (Haug et al. 2011b). Removal of At least ocular segment and post‐ocular segments 1– the background and artificial colouring of the images 5 contribute to the head shield (eucrustacean ground were made using Adobe ®Photoshop. The original pattern condition). Additionally, post‐ocular seg- images with background are deposited in the digital ments 6–9 (thoracic segments 1–4) appear to lack a repository MorphDBase. The figures were created free dorsal identity (Figs 3K, 4C) and thus are inter- using the free software GNU Inkscape. preted as contributing to the shield, also being part of the functional head (cephalothorax). Measurements and scatter plot Shield Once the specimens were documented, we used the images to take morphometrical measurements with In lateral view, outline bottle‐shaped; anterior region ImageJ (public domain). The following measure- narrower, elongated, forming a kind of 'neck'; shield ments were taken from the fossils: (1) body length, widening towards the posterior end. Two prominent from the anterior margin of the shield to the poste- furrows running in anterior–posterior direction rior margin of the sixth (last) pleon segment; (2) (Fig. 3D, E). First furrow extending backwards from length of the sixth pleon segment; (3) height of the antero‐lateral margin, reaching to the region where sixth pleon segment, from the middle of the segment; the shield widens. Second one extending from (4) length of the shield, from the dorso‐anterior to antero‐lateral margin backwards, not reaching the the dorso‐posterior margin of the shield; and (5) middle of the shield. Furrow arrangement in dorsal length of the prolongation of the shield, from the view not accessible due to orientation. Posterior dorso‐anterior margin of the shield to the rostral fur- shield margin almost straight, slightly concave, partly row (see paragraph ‘Shield’ in Results for explanation overhanging trunk segments laterally. of the furrow). The measurements were taken in millimetres and Ventral structures of functional head then normalized by dividing each of the values by the respective body length. From the normalized val- Ocular segment recognizable by prominent stalked ues, two ratios were formed: (1) length of sixth pleon eye structures (lateral eyes). Eyes extending forward segment/height of sixth pleon segment; and (2) beyond the anterior margin of the shield. LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 5

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Fig. 3. Francocaris grimmi. A, macro‐photography image. B–D, F–J, composite auto‐fluorescence microscopy images. E, restoration draw- ing of the shield, based on specimens SNSB – BSPG 1983 I 154 and SMNS 70520/3. ant, antenna; as, antenna scale; at, anterior; e, eye; ha, head appendages; lb, labrum; lf, lateral furrow; md, mandible; mdp, mandibular palp; mf, median furrow; mx, maxilla; mxp, maxilliped; p, pleon; pp1–5, pleopod 1‐5; ps1–6, pleon segment 1–6; pt, posterior; rf, rostrum furrow; s, shield; t, telson; th, thorax; ts5–8, thorax segment 5–8; tp(7–8), thoracopods (7–8); u, uropods.

Eye stalk (‘ocular peduncle’) short, cornea cylin- bearing endopod and exopod (antennal scale; drical and directing outwards (Figs 3G–I, 4A, B). scaphocerite). Endopod proximally with three Possible labrum present (Fig. 3J). prominent elements (Fig. 5A). The proximal one Post‐ocular segment 1, recognizable by poor (first) is the shortest. Second one is the longest, 3x remains of appendages, antennulae. Antennula repre- longer than the first. Third element slightly longer sented by two peduncle elements and two multi‐artic- than first (Fig. 5A, B). No remains of flagellum pre- ulated flagella arising from the distal part (Fig. 4A, B). served. Exopod (antennal scale) spatulate; longer Post‐ocular segment 2, recognizable by appen- than the three elements of the endopod combined dages, antennae. With proximal element (possible (Fig. 5A). Transversal furrow at about two‐thirds basipod; unclear if coxa is present or not) distally along the proximal–distal axis of the antennal scale 6 Pazinato et al. LETHAIA 10.1111/let.12382

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Fig. 4. Comparison of Francocaris grimmi and Eucopia grimaldii in lateral view. A–C, F, composite auto‐fluorescence microscopy images of F. grimmi. D, E, G, I, composite auto‐fluorescence microscopy images of E. grimaldii. H, schematic drawing of a cross‐section of the pleon segments of E. grimaldii. ant, antenna; ?ant, possible remains of antenna; ?as, possible remains of antennal scale; atl, antennula; e, eye; ec, eye cornea; en, endopod; ex, exopod, ep, eye peduncle; mxp, maxilliped; oo, oostegites; pp, pleopods; pp2, pleopod 2; ppm, pleopod musculature; ps1–6, pleon segment 1–6; s, shield; st, sternite, t, telson; tg, tergite; tp2–8, thoracopod 2–8; ts5–8, thorax segment 5–8; u, uropods.

(Fig. 5A). Margins of exopod apparently smooth, no remains of maxillulae preserved. Indications of setae or spines preserved. Exopod often broken at paired maxillae present. distal portion, remains of it present in several speci- Post‐ocular segment 6, recognizable by proximal mens. elements of an appendage; slightly differing from fur- Post‐ocular segments 3–5, recognizable by possible ther posterior appendages, indicating that it might remains of appendages (mouth parts). Appendages represent a specialized maxilliped (Fig. 3H, J). of post‐ocular segment 3, mandibles, appear heavily Post‐ocular segments 7–9, recognizable by proxi- sclerotized proximally (Figs 3H, J, 5A, 6B), with a mal elements of rather slim‐appearing appendages long and thin distal part (mandibular palp). No (Figs 3F, 4C). LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 7

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Fig. 5. Comparison of details of Francocaris grimmi and Eucopia grimaldii.A–C, composite auto‐fluorescence images of F. grimmi.A, head region in ventral view. B, C, thoracopod 7. D–I, composite bright‐field images of E. grimaldii. D, E, J, K, thoracopod 7. F, G, thora- copod 4. H, I, thoracopod 1 (maxilliped). ae1–3, antennal element 1–3; as, antennal scale; asf, antennal scale furrow; b, basipod; c, carpus; cx, coxa; d, dactylus; e, eye; ex, exopod; i, ischium; m, merus; mp, mouth parts; oo, oostegites; p, propodus; s, shield.

and 8 (post‐ocular segments 11, 12 and 13) Free thorax segments (thoracic segments 5–8; – ‐ – increase gradually in length in anterior posterior post ocular segments 10 13) direction. Post‐ocular segments 10–13, with dorsal scleroti- zation (tergites). Similar in shape. Posterior mar- Appendages of free thorax segments gin of each segment overlapping with the anterior margin of the subsequent one (Figs 3K, 4C). Tho- Remains of thoracopods preserved. Biramous (carry- racic segment 5 (post‐ocular segment 10) partially ing an endopod and exopod). Slender endopods, dis- covered by the shield in lateral view. Posterior tally broken off and remains of exopods, with no half of segment exposed. Thoracic segments 6, 7 details due to poor preservation (Fig. 3G, K). 8 Pazinato et al. LETHAIA 10.1111/let.12382

Thoracopod 7 entirely preserved, including the distal region (Fig. 5B, C). Extremely elongated, direc- Growth ted forwards. With seven elements, coxa, basipod, The measurements point to different size classes in five endopod elements. No remains of exopod pre- the data set (Suppl S1). This variation in size indi- served. Coxa and basipod short. Ischium (endopod cates different ontogenetic stages. When we plot element 1) slightly shorter than basipod. Barrel‐ the normalized ratio of length of pleon segment 6/ shaped merus (endopod element 2), middle portion height of pleon segment 6 versus the normalized ra- almost twice the width of proximal and distal edges, tio of length of shield/length of prolongation of the widest of the elements. Slender and long carpus (en- shield, the data points form a rather continuous line dopod element 3), about twice the length of merus. (Fig. 7), indicating an ontogenetic series without Propodus (endopod element 4) slightly shorter than strong allometric changes. carpus. Proximal edge wide. Middle portion wider than distal edge. Distal edge slender. Curved back- Preservation of internal tissue wards. Long spines at the mid‐portion of the ele- ment. Dactylus (endopod element 5) slender, claw‐ Remains of cylindrical digestive tube preserved along shaped. About half the length of the propodus. Lat- the midline of the body (Fig. 8A). eral edge smooth. Median edge armed with spines. Directed inwards, closing against the median edge of the propodus. Distal elements forming a jackknife‐ Discussion like sub‐chela (Figs 5B, C, 6A, B). Morphological details observed Pleon Our re‐investigation, especially with use of composite Six segments and a telson. Each segment overlapping fluorescence microscopy, reveals new details of the the subsequent one, with exception of pleon seg- morphology of Francocaris grimmi,allowingarestora- ments 5 and 6. All segments decreasing slightly in tion of the species in lateral view (Fig. 9). The massive height. Pleon segments 1–5 slightly decreasing in sub‐chela‐forming thoracic appendage inserts on tho- length. Pleon segment 6 is the longest, about 2× racic segment 7. Broili (1917) suggested, with question longer than the previous one (Figs 4C, 6A, B). Ellip- mark, that the enlarged appendage could arise from tical structure on lateral face of pleon segments 1–5 the last thoracic segment, but could not determine the (Fig. 4F), lacking in some specimens (Fig. 4C). exact position and how it was attached to the thorax. Pleon curved ventrally towards the thorax. Preser- The endopod of this appendage is extremely elon- vation varies from completely outstretched (Fig. 2G, gated, reaching the anterior margin of the shield in Q) to angled from 50° to 90° in respect to the thorax lateral view, and is present in every specimen, more or (respectively, Fig. 2A, I). less complete. As for the other thoracic appendages, only poor slender remains are preserved in some of Pleon appendages the fossils (Fig. 3D, F). The pleon segments of Francocaris grimmi each Pleopods 1–5 of similar length and shape, with proxi- form a dorsal sclerite (tergite) and a ventral sclerite mal basipod, distally carrying two rami, endopod (sternite; Figs. 4H, 6B). The elliptical structures pre- and exopod. Basipod longer than wide. Endopod and sent on pleon segments 1–5 are most likely scars of exopod long, slender and multi‐annulated (Fig. 3K). musculature of the pleopods, as seen in extant species Pleopod 6, uropod, with proximal basipod, distally (compare Fig. 4F, G). These are not to be confused carrying two rami, endopod and exopod (Fig. 6A, B). with the so‐called pleural plates, a ventral extension Details difficult to determine due to poor preserva- of the tergite found in some representatives of tion. Exopod longer than endopod, flat, scale‐like. Mysida and Lophogastrida (Wittmann et al. 2014). Posterior portion of the exopod appears to be multi‐ Different ontogenetic stages of F. grimmi are pre- annulated. served (Fig. 2). However, there seem to be no sub- stantial changes of the morphology throughout Telson growth (Fig. 7). Although one specimen showed con- siderable difference (specimen SMNS 70520/2, Fig. 2 Telson about 70% the length of pleon segment 6; N), this is probably due to imprecise measurements shorter than uropods. Margins apparently smooth caused by very poor preservation. However, as this is and narrowing towards the posterior portion (Figs 3 also the smallest specimen of the study, it was impor- K, 6A, B). tant to keep it in the data set. LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 9

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Fig. 6. Comparison of Francocaris grimmi and Eucopia grimaldii in ventral view; composite auto‐fluorescence microscopy images. A, B, F. grimmi.C,D,E. grimaldii. Abbreviations: ant, antenna; as, antenna scale; e, eye; ec, eye cornea; en3–8, endopod of thoracopod 3–8; ep, eye peduncle; ex2–8, exopod of thoracopod 2–8; md, mandible; mdp, mandibular palp; mp, mouth parts; oo, oostegites; pp1–5, pleopod 1–5; ps1–6, pleon segment; rt, remains of thoracopods 1–6; s, shield; st, sternites; t, telson; u, uropods

Fig. 7. Graphical representation of ontogenetic stages of Francocaris grimmi specimens used for this study. All values are normalized. 10 Pazinato et al. LETHAIA 10.1111/let.12382

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Fig. 8. Comparison of Francocaris grimmi with similar appearing crustaceans. A, composite auto‐fluorescence image of F. grimmi in lat- eral view; note the preserved digestive tube. B, C, composite macro‐photography images of larvae. D, composite macro‐ photography image of a prawn (Lucifer sp.). ant, antenna; as, antennal scale; atl, antennula; ct, cephalothorax; cta, cephalothorax appen- dages; dt, digestive tube; e, eye; mp, mouth parts; pp1–5, pleopod 1–5; ps1–6, pleon segment 1–6; s, shield; u, uropods.

Fig. 9. Restoration of Francocaris grimmi Broili, 1917.

possessed a shield enveloping all or nearly all tho- Systematic position of Francocaris grimmi: the racic segments (post‐ocular segments 6–14). From historical view this group, he considered the fossil more closely Broili (1917) described F. grimmi as a small crus- related to Mysidacea (including Lophogastrida, tacean with a very thin exoskeleton, which appeared Mysida and Stygiomysida). He based this decision on poorly calcified. He assigned this fossil to the group the shield being only formed by (‘attached to’) the ‘Thoracostraca’, today no longer considered to be a anterior segments of the thorax but he expressed natural group. At the time, the group included reservations due to the absence of modified posterior shrimps, lobsters and similar crustaceans that thoracic appendages, as present in F. grimmi,in LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 11 many (or most) extant species of Mysidacea. He used to separate lophogastridans from mysidans therefore considered extant groups that possess such (Meland et al. 2015; Feldmann et al. 2017). However, specialized appendages as, for example, species of this character alone only helps to exclude a species or Stylocheiron, a euphausiacean, commonly known as specimen from being an ingroup of Mysidae. Franco- , as well as species of Lucifer, a decapodan prawn, caris grimmi does not seem to possess a statocyst and which have an extremely elongated anterior region of is therefore unlikely a representative of Mysidae. the head (Fig. 8D). However, Broili (1917) also So far, known representatives of Mysida and Sty- argued against a closer relationship of F. grimmi to giomysida possess straight ‘pediform’ endopods on Euphausiacea and Decapoda due to the organization the posterior thoracopods. Although sub‐chelate of the cephalothorax, embracing all thoracic seg- appendages occur in ingroups of Mysida (Petaloph- ments in the (adult) forms of these two groups. thalminae and Heteromysinae), these are positioned more anteriorly on the body, on thoracopods 1 and 2 Systematic position of Francocaris grimmi: in Petalophthalminae and on thoracopod 3 in expanded view Heteromysinae. Only Lophogastrida species are known to possess sub‐chelate thoracic appendages Due to the overall body organization, an ingroup arising far posterior on the body, comparable to position of F. grimmi within seems those apparently present in F. grimmi. beyond doubt. It furthermore does not possess any of the prominent characters of adults of Lophogastrida (movable rostrum, triflagellate antennula, enlarged pleon). Likewise, no specialized characters of Syncar- The group Lophogastrida consists of four ingroups: ida are apparent (most important, the very short Peachocarididae (with exclusively fossil representa- shield). tives), Gnathophausiidae, Eucopiidae and One might now argue that by identifying F. ; the last three groups have extant grimmi as a eumalacostracan and by excluding representatives. These four groups are distinguished Hoplocarida, , Decapoda and Euphausi- mainly (but not only) by the number of thoracic acea, a closer relationship to Neocarida seems likely. appendages with their distal elements forming sub‐ Yet, it is less simple than that. The presence of free chelae (Wittmann et al. 2014). thoracic tergites and a long shield is, of course nowa- Peachocarididae Schram, 1986 was erected to days, only found within Mysidacea, hence an ingroup accommodate two fossil species from the Carbonifer- of Neocarida and Peracarida, but both characters are ous of the United States of America, Peachocaris plesiomorphies. Thus, in principle also many forms strongi (Brooks, 1962) and Peachocaris acanthouraea of the early evolution of Eumalacostraca branching Schram, 1984 (Schram 1986). Peachocaris strongi off all the mentioned lineages will possess such a was originally described as Anthracophausia strongi morphology. Still, we will concentrate in the follow- by Brooks (1962) and then renamed as Peachella ing on identifying possible apomorphic characters strongi by Schram (1974). Yet, as the name Peachella for Mysidacea or one of its ingroups in F. grimmi. was already occupied for a Cambrian trilobite, The relationships of the three major ingroups of Schram (1976) changed the name again to Pea- Mysidacea (Lophogastrida, Mysida and Sty- chocaris strongi. giomysida) have been heavily debated in the last few It is unlikely that Peachocarididae represents a decades (see Wittmann et al. 2014 for a review), natural group. In fact, it is even questionable that especially due to the fact that phylogenetic recon- both fossil species are representatives of Lophogas- structions based on morphological characters (Wir- trida at all. P. strongi was also considered to be a fos- kner & Richter 2007, 2010) differ from the ones sil representative of Euphausiacea (Brooks 1962) based on molecular data (Spears et al. 2005; Meland because of its caridoid appearance and all thora- & Willassen 2007). Currently, the monophyly of copods being biramous and unmodified. Yet, it was Lophogastrida (Richter 2003) and Mysida (Witt- reinterpreted as a lophogastridan (Schram 1974, mann 2013) is strongly supported. The monophyly 1976; 1986). The characters used for this interpreta- of Stygiomysida is not clear, and its position within tion are as follows: ‘well‐developed abdominal pleura, Mysida or as sister group of Mysida remains open pleopods, and thoracopods (this last with a well‐de- (Meland & Willassen 2007; Meland et al. 2015). veloped peduncle at the base of the exopods), and the Representatives of Mysidae (large ingroup of apparent lack of uropodal statocysts’ (Schram 1986, Mysida) possess a statocyst, a balance organ, in the p. 124). As already pointed out, these characters are proximal part of the endopods of the uropods (Witt- all plesiomorphies. The apparent lack of a statocyst mann et al. 2014). The lack of this character has been tends to exclude the fossils from being a 12 Pazinato et al. LETHAIA 10.1111/let.12382 representative of the ingroup Mysidae, but does not between dactylus and propodus appears straight, as support a position within Lophogastrida. seen in pediform appendages. In addition, the surface Peachocaris acanthouraea is based on isolated fos- of the appendages is smooth, not armed with spines. sil remains of the last three pleon segments and the A similar arrangement seems present in Schimperella tail fan (Schram 1984). With this, it provides even accanthocercus (Taylor et al. 2001) and Schimperella fewer characters arguing for lophogastridan affinities sp. (Larghi & Tintori 2007; Kriẑnar & Hitji 2010). than P. strongi. Peachocarididae is therefore not fur- Yunnanocopia grandis and Yunnanocopia longi- ther considered here. cauda were both described from the Anisian As mentioned above, the three groups of Lopho- (~245 Ma, Middle Triassic) of China (Feldmann gastrida with extant representatives are easily distin- et al. 2017). Unfortunately, thoracopods are not pre- guished by the number of thoracic endopods with served in any of the two species. The characters used the distal elements forming a sub‐chela. In represen- for the association with Eucopiidae represent similar- tatives of Lophogastridae and Gnathophausiidae, the ities and are all plesiomorphies within Peracarida. first and/or the second thoracopods are modified, These are, for instance, absence of pleural plates, forming a distal sub‐chela; the remaining thoracic presence of pleopods and at least six pairs of ooste- endopods are pediform, while in representatives of gites (specialization of thoracic epipods of females Eucopiidae, thoracopods 2–7 are modified, forming a that support the ). sub‐chela (Wittmann et al. 2014). Hence, as in F. Eucopia praecursor is from the Callovian grimmi, the thoracopod 7 bears a sub‐chela in the lat- (~165 Ma, Middle Jurassic) of France. The species is ter. known only from two specimens from the La Voulte Lagerstätte. It is a small shrimp‐like crustacean, Eucopiidae about 20 mm long, which possesses three to four free thoracic segments and elongated and slender thora- Eucopiidae includes eight species in the modern copods. The combination of these two characters was fauna, all in Eucopia. In all representatives of Euco- used to place E. praecursor within Eucopiidae (Secre- pia, the first pair of thoracopods is modified into tan & Riou 1986). Unfortunately, the distal portion maxillipeds (Fig. 5H, I) and thoracopods 2, 3 and 4 of the thoracopods is not well preserved. Therefore, are short, strong and sub‐chelate (Fig. 5F, G), it remains unclear whether it possesses sub‐chelae. strongly contrasting with slender and elongate sub‐ Hence, none of the supposed fossil representatives chelate thoracopods 5–7 (Fig. 5D, E J, K; Wittmann of Eucopiidae shows clear apomorphic characters of et al. 2014). Thoracopod 8 is also slender, but not as this group. For species of Schimperella, it remains elongated as the previous ones and does not possess unclear whether they are representatives of Per- a sub‐chela (Wittmann et al. 2014). acarida at all. Their habitus is compatible with sev- At least six fossil species have been interpreted as eral positions within Eumalacostraca. The species of representatives of Eucopiidae: Schimperella beneckei Yunnanocopia can be identified as representatives of Bill, 1914, Schimperella kessleri Bill, 1914, Schim- Peracarida based on the presence of oostegites, yet perella accanthocercus Taylor, Schram & Yan‐Bin, any further narrowing down remains impossible. 2001, Yunnanocopia grandis Feldmann, Schweitzer, The species praecursor Secrétan & Riou, 1986 could Hu, Huang, Zhou, Zhang, Wen, Xie, Schram, Jones, in principle be in fact an ingroup of Eucopiidae and 2017, Yunnanocopia longicauda Feldmann, Sch- Eucopia, based on the elongate thoracopods, yet weitzer, Hu, Huang, Zhou, Zhang, Wen, Xie, Schram, without preservation of the distal elements this Jones, 2017, and Eucopia praecursor Secretan & Riou, remains a rather weak character. Given the uncer- 1986. Yet, all these fossils do not clearly possess apo- tainties of all so far supposed fossil representatives of morphies of the group, but are characterized by ple- Eucopiidae, we restrict further comparison to the siomorphies. more informative extant forms. Schimperella kessleri and Schimperella beneckei ~ come from the Triassic (Olenekian to Anisian, 251 Could Francocaris grimmi be a representative to 245 Ma) of France. A relationship to Eucopiidae of Eucopiidae? was based on the fact that ‘medium thoracic legs are the longest, and the dactylus is formed as a strong Francocaris grimmi shares with modern representa- and slightly curved claw’ (Bill 1914, p. 313; translated tives of Eucopiidae, hence those of Eucopia, the pres- from German original). Yet, the joint responsible for ence of an elongated thoracopod 7 with a sub‐chela the maximum curvature of the supposed claw formed by propodus and dactylus, both elements appears to be between the carpus and propodus, not being armed with spines. There are no clear apomor- between the propodus and dactylus. The joint phic characters of Neocarida, Peracarida, or LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 13

Lophogastrida visible in F. grimmi, yet the observable The elongation of the anterior head region. – Com- details are at least compatible with such an interpre- paring F. grimmi to its possible closer relatives, the tation. elongation of the anterior head region is clearly an Unfortunately, it remains unclear how the distal autapomorphic character of this species. However, parts of thoracopods 2–6 were organized in F. such elongations by which the segments of the eyes, grimmi. It is possible that all of them were sub‐che- antennulae and antennae are separated by a long dis- late (as in representatives of Eucopia), yet we simply tance from the next segment, that is that of the lack this detail. The complexity of the shared charac- mandibles, are known in some other representatives ter – sub‐chelate, elongate thoracopod 7 armed with of Eumalacostraca. prominent spines – provides at least a conclusive As Broili (1917) noted, such a morphology is indication of a close relationship of F. grimmi and known in prawns of the group Lucifer (Fig. 8D). Eucopia, yet it depends on a number of assumptions Other groups of Eumalacostraca show such an elon- on the morphology of F. grimmi that have not been gation especially in their larval forms, for example directly observed. This does not only account for the the alima‐type larvae of mantis shrimps (Fig. 8B, C), distal parts of the anterior thoracopods, but also, for although in adults mantis shrimps the distance example, for a marsupium formed by oostegites in between the antennae and the mandibles is also quite females. large (Haug et al. 2012). Other larvae with an elon- Furthermore, if accepting a possible sister group gated anterior region of the head are those of spiny relationship of F. grimmi and Eucopia there are still and slipper lobsters (Palero et al. 2014), and of the two possibilities for the reconstruction of character species reynaudii (Kutschera et al. evolution: (1) the stem species (≈ last common 2012). ancestor) of both could have possessed three elongate It is interesting to note that this character appears thoracopods (5–7) and this condition was retained to have independently evolved in at least three differ- by Eucopia, while the presence of only one long sub‐ ent types of larvae. Also, the adults of Lucifer appear chelate appendage is an autapomorphy of Franco- larviform overall and are regularly misidentified as caris grimmi; (2) the stem species could have had larvae in many samples (own observations only one long appendage, Francocaris grimmi from different museum collections). It is therefore retained the long thoracopod 7, and the presence of tempting to suggest that the extreme elongation in F. three of such appendages is an autapomorphy of grimmi is originally a type of larval character retained Eucopia (Fig. 10). into adulthood. Yet, as it is an ingroup of Peracarida, Based on the discussion of the morphology of F. its ontogeny does not include a pronounced larval grimmi and different ingroups of Eumalacostraca phase. Hence, there is no support for such assump- above, we propose that Francocaris grimmi is a repre- tion. Moreover, the reverse, the elongation extending sentative of the Lophogastrida ingroup Eucopiidae. over ontogeny, appears to be unlikely too, based on the known preserved specimens forming part of the Comparative morphology: morphological ontogeny. peculiarities of Francocaris grimmi The structure of the sub‐chela. – The propodus and There are three morphological aspects of Francocaris dactylus of thoracic appendage 7 form a prominent grimmi that demand further consideration in a com- grasping structure. The principle arrangement is gen- parative frame: erally categorized as a sub‐chela. Yet, the propodus is not straight, and it is curved laterally, changing some of its functional aspects. ‘Normal’ sub‐chelae with straight propodi have to grasp around the to‐be‐ grasped object as the angle of opening is directed strongly backwards. A true chela can grasp an object from behind, as the opening angle is oriented for- ward. Mantis shrimps optimize their prey catching by the principle Z‐shaped arrangement of the entire appendage. By this arrangement, the angle of open- ing becomes shifted further anteriorly. The sub‐chela of F. grimmi probably allowed to grasp around an Fig. 10. Two hypotheses about the presumed character evolution on the lineage towards Francocaris grimmi and the species of object in a similar way to mantis shrimps. The Eucopia. Tp, thoracopod. propodus, laterally curved outwards, provides an 14 Pazinato et al. LETHAIA 10.1111/let.12382

B J

A

K

C

L D

E

M

N HI

F

G

Fig. 11. Comparison of the sub‐chelae of thoracopod 7 of different species. A, B. Eucopia crassicornis. A, overview. B, close‐up of sub‐ chela. C–I, Eucopia grimaldii.G–I, high magnification images (60× objective, resulting in c. 600× magnification) of the sub‐chela, showing the inner row of spines of the dactylus and inner row of spine‐like‐setae of the propodus. J–N, Francocaris grimmi. Abbreviations: ant, antenna; atl, antennula; d, dactylus; ds, dactylus spines; p, propodus; ps, propodus spines; tp6–8, thoracopod 6–8. arrangement distantly comparable to the Z‐shaped Although also heavily armoured, the sub‐chelae in appendages in mantis shrimps. representatives of Eucopia are significantly smaller Similarities in size, equipment with massive spines, than those of F. grimmi also indicating differences in and the optimization of the opening angle of Franco- possible prey size (Fig. 11). caris grimmi and mantis shrimps provide an indica- tion that F. grimmi likewise used its appendages for Position of the appendage bearing the sub‐chela. – grasping prey items. Unfortunately, we do not know Sub‐chelate appendages occur in various lineages of details about the feeding behaviour of extant repre- Euarthropoda(Fig.12).Yet,thoseofF. grimmi are sentatives of Eucopia which could provide additional remarkable in that they are so far posterior. Within indications for the feeding biology of F. grimmi. Euchelicerata, sub‐chelate appendages are known on LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 15

A C

B

E

F D

G H

I

J

Fig. 12. Schematic drawing of the head and thoracic region of a euarthropodan, illustrating the position of grasping appendages in differ- ent groups. A, chelicera of a web spider. B, pedipalp of an armoured harvestman. C, pedipalp of a whip spider. D, maxilla of a remipedian; from Haug et al. (2014b). E, labium of a dragonfly larva. F, raptorial leg of a fossil cockroach, from Dittmann et al. (2015). G, I, raptorial leg of stomatopod larvae. H, maxilliped 3 of a slipper lobster. J, raptorial appendage of a phyllosoma larva. Abbreviations: o, ocular seg- ment; po1–13, post‐ocular segment 1–13. post‐ocular segment 1, for example the chelicera in segment 7. The following segments, post‐ocular seg- web spiders (Araneae), and also on post‐ocular seg- ments 8–10, have sub‐chelate appendages as well. ment 2, for example the pedipalp in armoured harvest- Comparably, the sub‐chelate 'gnathopods' of men (Opiliones, Laniatores), dwarf whip scorpions amphipodan crustaceans arise from post‐ocular seg- (Schizomida) and whip spiders (Amblypygi). ments 7 and 8. More rarely also some forms of Further rather anterior sub‐chelate appendages are Insecta have sub‐chelate appendages on post‐ocular present in remipedian crustaceans on post‐ocular segment 7, such as gladiators (Mantophasmatodea) segments 4, 5 and 6, that is maxillula, maxilla and or predatory bush crickets (Saginae), and on post‐oc- maxilliped. Many representatives of Insecta also have ular segment 8 (larval forms of Trichoptera). sub‐chelate appendages on these segments. The 'rap- Francocaris grimmi is hence rather unusual in hav- torial mask' of odonatan larvae is in principle ing a sub‐chelate appendage on post‐ocular segment arranged as two sub‐chelae, as this derived labium 12. As pointed out, modern forms of Eucopia also represents the conjoined appendages of post‐ocular have a sub‐chela on this segment. Other examples segment 5. Numerous examples can be found for are ‘podotrematan’ brachyuran crabs and phyllo- sub‐chelate appendages on post‐ocular segment 6, soma larvae of spiny and slipper lobsters. ‘Podotre- for example in mantises (Mantodea) and their closer matan’ crabs use the sub‐chelate appendages on relatives (Dittmann et al. 2015), water scorpion bugs post‐ocular segment 12 and 13 to carry objects allow- (Nepidae, Belostomatidae), mantis lacewings (Man- ing them to hide or better camouflage under them tispidae) and many others. In mantis shrimps, this (Guinot & Wicksten 2015). Phyllosoma larvae appendage has also a small sub‐chela, yet it is clearly appear to grab prey with their sub‐chela‐like appen- not used for grasping, but for cleaning. dages on post‐ocular segments 9–12 (Jeffs 2007). The most anterior functional sub‐chelate appen- Therefore, besides F. grimmi only extant species of dage in mantis shrimps arises from post‐ocular Eucopia and phyllosoma larvae appear to use sub‐ 16 Pazinato et al. LETHAIA 10.1111/let.12382 chelate appendages on post‐ocular segment 12 for References feeding. Like in F. grimmi, these are very elongated. Arratia, G., Schultze, H.P., Tischlinger, H. & Viohl, G. 2015: Soln- Yet, unlike in F. grimmi, in phyllosoma larvae several hofen – Ein Fenster in die Jurazeit, 620 pp. Dr Friedrich Pfeil pairs of appendages are involved in preying, while it Verlag, München. Barthel, K.W. 1978: Solnhofen. Ein Blick in die Erdgeschichte, 393 appears that F. grimmi relied primarily on this elon- pp. Ott Verlag, Thun. gated appendage. This appears to be a so far unique Barthel, K.W., Swinburne, N.H.M. & Conway Morris, S. 1990: type of morphology and supposed feeding strategy. Solnhofen: A Study in Mesozoic Palaeontology, 236 pp. Cam- bridge University Press, Cambridge. Bill, P.C. 1914: Über Crustaceen aus dem Voltziensandstein des Elsasses. Mitteilungen der Geologischen Landesanstalt von Conclusions Elsaß‐Lothringen 8, 289–338. Broili, F. 1917: Eine neue Crustaceen‐(Mysidaceen‐)Form aus dem lithographischen Schiefer des oberen Jura von Franken. In this re‐description of Francocaris grimmi Broili, Centralblatt für Mineralogie, Geologie und Paläontologie 19, 1917, we report new details of the species concerning 426–429. Brooks, H.K. 1962: The Paleozoic Eumalacostraca of North its systematic interpretation, its evolution and its America. Bulletins of American Paleontology 44, 163–335. morphology: Dittmann, I.L., Hörnig, M.K., Haug, J.T. & Haug, C. 2015: Rapto- blatta waddingtonae n. gen. et n. sp. – an Early Cretaceous ‐ roach‐like insect with a mantodean‐type raptorial foreleg. 1 The presence of the elongated and sub chelate Palaeodiversity 8, 103–111. thoracic appendage 7 appears to be a synapomor- Feldmann, R.M., Schweitzer, C.E., Hu, S., Huang, J., Zhou, C., phy of F. grimmi and Eucopia, hence an autapo- Zhang, Q., Wen, W., Xie, T., Schram, F.R. & Jones, W.T. 2017: Earliest occurrence of lophogastrid mysidacean morphy of Eucopiidae, including F. grimmi. Other (Crustacea, Eucopiidae) from the Anisian Luoping Biota, Yun- characters of F. grimmi are in concordance with nan Province, China. Journal of Paleontology 91, 100–115. this suggestion, such as well‐developed pleopods Garassino, A. & Schweigert, G. 2006: The Upper Jurassic Solnho- fen decapod crustacean fauna: review of the types from old and pleon segments without projecting pleurae. descriptions (infraorders Astacidea, Thalassinidea, and Palin- 2 Due to the lack of apomorphic characters, most ura). Memorie della Società Italiana di Scienze Naturali e del supposed fossil representatives of Eucopiidae Museo Civico di Storia naturale in Milano 34,1–64. Guinot, D. & Wicksten, M.K.2015: Camouflage: carrying beha- should be treated with caution. viour, decoration behaviour, and other modalities of conceal- 3 The presence of a massive sub‐chela, heavily ment in Brachyura. In Castro, P., Davie, P.J.F., Guinot, D., armoured with spines, suggests that Francocaris Schram, F.R. & Von Vaupel Klein, J.C. (eds): Decapoda: Bra- chyura (Part 1), Treatise on Zoology‐Anatomy, , Biol- grimmi was a predator. ogy, volume 9C–I, 583–638. Brill, Leiden and Boston. 4 The use of mainly the appendages of post‐ocular Haug, J.T. & Haug, C. 2013: An unusual fossil larva, the ontogeny segment 12 for preying would so far be unique for of achelatan lobsters, and the evolution of metamorphosis. Bul- letin of Geoscience 88, 195–206. Euarthropoda. Haug, J.T. & Haug, C. 2015: ‘Crustacea’: Comparative aspects of larval development. In Wanninger, A. (ed): Evolutionary Devel- opmental Biology of Invertebrates 4: Ecdysozoa II: Crustacea,1– Acknowledgements. – We thank Alexander Nützel and Mike 37. Springer, Vienna. Reich from the Bayerische Staatssammlung für Paläontologie Haug, J.T. & Haug, C. 2016: ‘Intermetamorphic’ developmental und Geologie, Munich, Matthias and Marina Wulf, Rödelsee, stages in 150 million‐year‐old achelatan lobsters – The case of Martin Sauter, Freising, Roger Frattigiani, Laichingen, and the species tenera Oppel, 1862. Structure & Develop- Udo Resch, Eichstätt, for providing the fossil specimens that ment 45, 108–121. made this study possible. We thank also Stefan Friedrich and Haug, J.T. & Haug, C. 2017: A new glimpse on Mesozoic zoo- Roland Melzer from the Zoologische Staatssammlung plankton—150 million‐year‐old lobster larvae. PeerJ 5, e2966. München for kindly loaning the extant material of E. grimal- Haug, J.T., Haug, C. & Ehrlich, M. 2008: First fossil stomatopod dii, and Laure Corbari from Muséum national d'Histoire nat- larva (Arthropoda: Crustacea) and a new way of documenting urelle, Paris, for providing access to the specimen of E. Solnhofen fossils (Upper Jurassic, Southern Germany). Palaeo- crassicornis. We are grateful to the institutions who kindly diversity 1, 103–109. funded this project: Capes/Doctoral Program (Process n°. Haug, C., Haug, J.T. & Waloszek, D. 2009a: Morphology and 88887.161379/2017‐00; PGP), Dept. Origines et Evolution, ontogeny of the Upper Jurassic mantis shrimp Spinosculda ehr- MNHN (project PerSysT; CJ), Deutsche Forschungsgemein- lichi n. gen. n. sp. from southern Germany. Palaeodiversity 2, schaft (DFG Ha 6300/3–2; JTH), LMU (LMUexcellent; CH) 111–118. and Volks‐wagen Foundation (Lichtenberg professorship; JTH). Haug, J.T., Haug, C., Waloszek, D., Maas, A., Wulf, M. & Sch- We thank Rodney Feldmann and an anonymous reviewer for weigert, G. 2009b: Development in Mesozoic scyllarids and their very helpful comments on an earlier version of this implications for the evolution of Achelata (Reptantia, Deca- paper. P. G. Pazinato and C. Jauvion contributed equally to poda, Crustacea). Palaeodiversity 2,97–110. the paper. Haug, J.T., Haug, C., Maas, A., Kutschera, V. & Waloszek, D. 2010: Evolution of mantis shrimps (Stomatopoda, Malacos- traca) in the light of new Mesozoic fossils. BMC Evolutionary Data availability statement Biology 10, 290. Haug, J.T., Haug, C., Waloszek, D. & Schweigert, G. 2011a: The Original images of this study are available in the importance of lithographic limestones for revealing ontogenies < // in fossil crustaceans. Swiss Journal of Geosciences 104,85–98. MorphDBase digital repository: http: morphdba Haug, J.T., Haug, C., Kutschera, V., Mayer, G., Maas, A., Liebau, se.de> S., Castellani, C., Wolfram, U., Clarkson, E.N.K. & Waloszek, LETHAIA 10.1111/let.12382 Eumalacostracan crustacean from Solnhofen 17

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Supplement S1. Measurements of shield and last Supporting Information pleon segment of Francocaris grimmi. Raw values and values divided by body length. Additional supporting information may be found online in the Supporting Information section at the end of the article.